Effects of drip application of Bacillus subtilis under salt stress on the growth and soil environment of cotton seedlings under filmless drip irrigation
The aim of this study was to elucidate the mechanistic underpinnings of the influence of Bacillus subtilis(BS)application via drip irrigation on the early growth of cotton seedlings and the soil environment under varying salinity stress conditions in southern Xinjiang.The experiment was conducted using a dual-factor split-plot design,with the main plot consisting of two salt gradients(S),including low salt(2 mS·cm-1)and high salt(5 mS·cm-1),and the sub-plot consisting of three BS dosage levels(B),i.e.,no BS application,low BS dosage(15 kg·hm-2),and high BS dosage(30 kg·hm-2).There were six treatments:S2B0,S2B15,S2B30,S5B0,S5B15,and S5B30.The effects of drip application of BS under salt stress on the main growth indicators of cotton,as well as the impacts on the activities of key soil enzymes,organic matter content,conductivity,and the structure of bacterial and fungal communities was investigated.The results showed that compared to low salt stress,high salt stress significantly reduced cotton growth parameters,soil urease activity,invertase activity,and organic matter content,leading to a decrease in the relative abundance of beneficial microorganisms(Zeaxanthinibacter)in the soil.Drip application of BS alleviated the inhibitory effect of salt stress on cotton growth,significantly increased soil urease activity and organic matter content,and reduced soil electrical conductivity.It also increased the relative abundance of beneficial microorganisms(Nitrospira,Woeseia,and Pseudogymnoascus)in the soil and decreased the relative abundance of harmful microorganisms(Phialophora).Compared to the control without BS application(S2B0 and S5B0),low(S2B15 and S5B15)and high(S2B30 and S5B30)dosages of BS treatment significantly increased stem dry weight of cotton by 20.62%-63.99% (P<0.05)and 30.85%-77.08% (P<0.05),and leaf dry weight by 27.84%-74.73% (P<0.05)and 40.83%-76.06% (P<0.05),respectively.The analysis results of the partial least squares path model indicated that BS indirectly promotes the improvement of cotton growth indicators under salt stress conditions by affecting soil enzyme activity,organic matter content,conductivity,and soil bacterial and fungal community structures.The effects of different doses of BS on the improvement of cotton seedling growth indicators and the improvement of saline soil environment under salt stress in southern Xinjiang were ranked as follows:30 kg·hm-2>15 kg·hm-2>no BS.
Bacillus subtilissalt stressfilmless drip irrigation cottonsoil microbial community structurepartial least squares path model
万方数据
维普
